


Under Your Skin

by profound-boning (farawaystardust)



Series: SPN A/B/O Bingo [4]
Category: Supernatural
Genre: Alpha Castiel (Supernatural), Alpha/Beta/Omega Dynamics, Alternate Universe - Gangsters, Anal Sex, Cliffhangers, First Time, Knotting, M/M, Omega Dean Winchester, Porn With Plot, Rimming, Scent Bonding, star-crossed lovers
Language: English
Status: Completed
Published: 2017-12-02
Updated: 2017-12-02
Packaged: 2019-02-09 10:36:45
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,773
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/12886065
Author URL: https://archiveofourown.org/users/farawaystardust/pseuds/profound-boning
Summary: A year ago, even six months ago, Dean believed in True Mates as a concept but he knew he didn’t have one. Or if he did, he knew he ought to save the poor bastard the trouble and avoid them at all costs.a plotty/sexy timestamp





	Under Your Skin

**Author's Note:**

> square filled: knotting  
> pairings: destiel  
> word count: 2.8k  
> tags: no warnings apply, a/b/o, mafia!au, alpha!cas, omega!dean, star-crossed lovers, porn with plot, first time knotting, rimming, anal sex, ENDS ON A CLIFFHANGER I'M SERIOUS

A year ago, even six months ago, Dean believed in True Mates as a concept but he knew he didn’t have one. Or if he did, he knew he ought to save the poor bastard the trouble and avoid them at all costs.

But the past four months have gone so much differently (and so much better) than Dean could have ever anticipated. He and Cas are able to covertly send messages about their schedules and arrange for short meetings sporadically. They’ve not been able to get more than an hour or two at a time, but Dean can’t complain when that time is filled with intelligent conversation, fun and humorous moments, and increasing amounts of devotion. Not to mention the sex. He’s constantly surprised just how quickly he’s become attached to Cas and then the next time they meet up, the surprise vanishes in the face of just how _good_ they are together.

He’d been right that Cas wants an Omega who speaks their mind and uses their own free will. Cas doesn’t want to be a domineering partner (although they are both on board with him taking the reins during their sex). In other parts of life, Cas would rather listen to what Dean has to say or defer to him entirely. This notion comes up in particular when discussing daily routines, seeing as Cas is incapable of doing more than putting together a simple sandwich and tying his shoes. Dean gets a great deal of joy out of putting his Alpha back together after they have sex, and grumbles a bit every time he thinks about one of Cas’s gang members helping him with his ties in the morning when Dean isn’t there to do it. Cas has assured him that both Hester and Inias are far too dedicated to ‘the cause’ to consider any ulterior motive to helping Cas into his clothes, but Dean still thinks he’d have a word with those two if he could.

Of course, thinking that he and Cas are in any way a regular couple who can bicker over silly domestic stuff is sheer lunacy. Their lives are too intense and unpredictable for a relationship with anyone, not to mention the danger they’re putting each other in by meeting up. When Dean lays in bed at night, he beats himself up inside for feeling possessive, for feeling needy, for wanting Cas as much as he does. Why should he risk their lives just because he likes the guy’s scent?

But the scent bond continues to grow. Flourishes, even. The longer they spend together, the more intimately they know one another, the more Dean is able to pick up subtle notes in Cas’s scent that he hadn’t been able to previously. Certainly more than he’d be able to smell in another person, even someone like Ash whom he’s known for a few years. Dean can now identify different flowers in the bouquet of Cas’s arousal, and it drives him to keep trying out new ideas in order to draw more beautiful smells and sounds from his Alpha. And when Cas uses his hands to bring Dean to climax, he babbles endlessly about Dean’s sweet taste and scent. Sometimes they have to not touch each other for a while afterwards to let their scents settle down, or else risk getting caught by their gangs.

Gordon, Alastair, and Azazel have all made comments to Dean about it, calling Dean a slut and making other lewd remarks. Dean doesn’t care as long as they don’t realize it’s just one partner, and more importantly that they don’t realize it’s _Castiel._

Actually, they try to talk about their gangs as little as possible. They both know the situation that they’re in; it doesn’t need to be brought up in the already too short moments that they do have together. Though it does come up when they talk about their pasts. Dean recalls night after night of cleaning up after John, of never really getting to be a kid. He speaks with pride about Sammy though, and Cas tells him his nostalgia smells like a warm leather jacket.

Cas’s saltwater sadness permeates the air when he relates his own story about getting involved with Crowley. Apparently, Cas was brought up in the life, with Crowley as his slimy pseudo-uncle. Cas, being the youngest of several siblings with parents who barely cared that he existed, was desperate to leave, to do _something._ Uncle Crowley was there. At first, he did simple things for Crowley like giving someone a ride or delivering an envelope to someone’s mailbox. But it escalated and, with the tasks, so did Cas. He didn’t care what Crowley was asking him to do and even started to enjoy it. Being big and strong enough to fight back? To push somebody around and get his way? That all sounded pretty good for a kid who’d been someone else’s punching bag for practically his whole life.

“It made me feel powerful,” Cas tells him. They’re curled up on the bed of a cheap motel room, paid for in cash for three hours. Dean doesn’t raise his head from where it’s resting on Cas’s chest, just runs his hand down Cas’s side and waits for him to finish his thought. “And Crowley kept encouraging me. Every successful mission, every bit of information I could get from a source, every… every kill. I was smart and obedient and eventually, I became as ruthless as him. Emotionless. Just doing what I thought needed to be done.”

Dean breathes in the scent of Cas’s remorse and sighs. “Doesn’t make you a bad person, Cas. You were doing what needed to be done. What would have happened if you started saying no? You’ve gotta keep yourself out of danger, and that’s what you did.”

Cas huffs. “Yes, I suppose, but that doesn’t mean I haven’t hurt many innocent people.”

“And some not-so-innocent ones,” Dean adds. “You were just saying that you’ve been working on taking down Dick Roman for a while now. If he’s really so involved, dude’s a scumbag and deserves it.”

That gets Cas to smile. “Indeed. But I will still mourn the people I’ve hurt, the things I can’t change.”

“Yeah, we’ve all got stuff like that.”

“Even you?”

“‘Course.” Dean snorts. “Haven’t seen my kid brother since he was starting puberty. I can’t even call him on the phone or they’ll catch me and find him and kill us both. I can’t let that happen, just like I couldn’t let him get hurt for my dad’s shit all those years ago.”

“You are very brave,” Cas says, bringing his lips to Dean’s hairline.

“Sure, Cas. I keep meeting up with you, don’t I?”

Cas pinches at Dean’s side to tickle him. “I’m being serious. You risked so much.”

“Not like I’m working for the greater good here, Cas.” Dean shrugs. “Dick Roman’s as crooked as they come. Maybe I should let you and Crowley take us down.”

Cas sighs. “I’m afraid it wouldn’t be that simple. Crowley fancies himself a king when really he’s a sewer rat.”

“Does that make you a big grumpy cat, chasing other rats for him?” Cas bites his ear in response. “Ouch!”

“Big grumpy cat,” Cas grumbles, wiggling to snuggle Dean’s body more closely to his own. “The nerve.”

“Shut up, little Alpha.” Dean hides his smile in Cas’s shoulder. This is a really nice change from the norm, being cooped up in the back of a van or a car; a bed, even in a musky motel room, feels like a luxury. They hadn’t even bothered to get undressed when they’d arrived, just fallen onto the soft mattress and curled around each other.

Dean tilts his chin up to give Cas a gentle kiss. Their lips meet again and again, heat building steadily. Dean, impatient, readjusts so that he’s curled over top of Cas, and moving to mouth at Cas’s neck. The noises Cas makes are divine, all gruff and all Alpha. He puts his hands on Dean’s ass, clearly appreciative of the thick muscle. Then Cas brings his hands to the hem of Dean’s shirts.

“Can I?” He breathes into Dean’s open mouth. Dean nods and shifts his weight over his knees so he can help without face planting. They both push Dean’s jacket and flannel off of his shoulders and Cas takes the time to kiss up his tummy upon stripping him of his t-shirt. Dean attacks Cas’s clothing with the same voracity, rendering the button down useless and button-free. Cas just smirks.

“Eager, I see.”

“Like you can resist,” Dean teases, pressing his slick ass down onto Cas’s lap. His Alpha whines at the contact and Dean feels vindicated.

But he only has a second to relish his control before Cas flips them over. It’s a show of strength that has Dean hardening further in his pants.

Now on top, Cas leans down to press a kiss to Dean’s happy trail. He looks up and meets Dean’s eyes before reaching for his belt. Dean feels instant relief and he wiggles his hips a bit, relishing his ability to tell just how turned on Cas is. Cas responds by biting down on Dean’s hip bone, and Dean sighs Cas’s name when Cas strips him out of his jeans. Dean, knowing damn well how good he must look right now, spread out naked on the bed, smirks.

“C’mon Alpha. You ready?”

The look in Cas’s eyes turns positively feral. He quickly and efficiently strips out of his own pants and briefs, revealing a large and beautiful cock. Fuck, he can see where Cas’s knot is ready to join in.

Dean reaches out one hand to Cas. “C’mere, let me taste you now.”

“Next time,” Cas promises, pumping himself once, twice. When Cas rocks back on his heels, he pushes at Dean’s thighs until they’re spread wide and bent to expose Dean’s hole. Cas’s wide tongue dives over and over again into him, licking and sucking at the slick and the muscle there.

And the best part is Dean can hardly hear his own moans over Cas’s—his Alpha seems to genuinely enjoy eating him out within an inch of his life.

“Cas,” Dean pants, fingers gripping at the sheet, at Cas’s hair, at his own hair. _“Castiel.”_

“Yes, Omega.” Cas bites down on his inner thigh. “What do you need? Anything.”

“Your knot. Please, Alpha. Fuck.”

Cas rises onto his knees and wraps one hand around his erection, seemingly to try and stop the urge to pop too early; the smell of lilacs and apple blossoms and Cas’s arousal increases.

“Are you sure?” he whines, blue eyes huge. “Dean, we’ve never—”

“I know but—but I want to, Cas.” He blushes. “C’mon.”

“Fuck, Dean, you’re so beautiful.” Those eyes travel up and down Dean’s heaving torso, his sweaty brow. “Beautiful and all mine.”

“Yes,” Dean agrees, stretching out to touch Cas’s gorgeous thighs with his fingertips. “Glad I found you.” He’d never let himself think too much about this, dream about being cared for and respected as an equal by his Alpha. Being loved like this. Dean knows he is so, so lucky to have found Cas and for Cas to be the kind of partner that he is, trusting and considerate and sweet. He’s practically perfect.

Aside from the whole rival gangs thing, that is. That could pose a problem to the white picket fence and happily ever after he’s been fucking daydreaming about.

“You’re thinking about something and it’s making you upset.” Cas lowers himself onto his forearms, his face close to Dean’s once more, his warm body covering Dean where he had begun to shiver without realizing. “We don’t have to do anything you’re not comfortable with, Dean, I—”

“No, Cas, that’s not it,” Dean interrupts. How do you tell your True Mate you’re worried about your boss ordering you to kill him? “I’m just—. It’s our jobs, our _lives,_ Cas. What’s going to happen when—?”

Cas shushes him gently and kisses him, running his free hand through Dean’s hair. “I can’t say exactly what will happen this week or the next or next month, Dean. I’m—I’m really not certain of anything anymore. The only thing that makes sense right now is being with you. Knowing you’re mine and that you want me to be yours. We can handle everything else as it comes, together.”

Dean blinks hard to dispel the tears and kisses Cas in response. He wraps his arms around Cas’s neck and holds on tight. He has to believe that they can overcome what’s next.

They kiss and kiss some more while Cas sinks two fingers deep into Dean’s wet hole. He adds another to make sure Dean is properly stretched and when he finds Dean’s prostate, he adds a fourth. By the time he pulls back again, Dean is a writhing mess beneath him.

 _“Cas,”_ Dean begs. “C’mon…”

Cas picks up one of Dean’s legs and gets closer. He pets one hand over Dean’s quivering belly and looks into his eyes. He doesn’t break that eye contact until he’s seated all the way inside, then he closes his eyes.

“Fuck, you feel amazing,” Cas says, sounding completely out of breath.

“You too, wow,” Dean groans, relishing the fairly painless stretch; Cas prepped him well. He arches his back a little to feel a different angle and sighs. Cas draws his hips back slowly and pushes forward again. Dean frees his legs from Cas’s hold and wraps his ankles around each other at the small of Cas’s back, pulling him down so they’re face-to-face. Dean whispers dirty promises as Cas continues to pump in and out of his ass, the smell of slick and mate and lust filling the room.

“You are so beautiful.” Cas punctuates every word with another precise thrust into Dean’s prostate, until Dean clings to Castiel’s shoulders and comes with one loud, long groan of _“Cas!”_ His fingers feel numb but he holds on anyway, not willing to be parted from his Alpha. His mate. Cas laves his tongue over the area on Dean’s neck where a bite would go. Dean almost wishes he would do it, would claim him here and now, but the risk is too great. For now, it is a deep purple hickey.

“I’m gonna touch that mark tomorrow and think of you,” he tells Cas, panting deep gulps of air. “I’ll be in my bunk and I’ll be thinking of you, Alpha. Give me your knot so I can remember you filling me up, too.”

With that, Cas’s knot pops and releases a flood of hot cum into Dean; he’s babbling mindlessly into the crook of Dean’s neck. Dean tugs on Cas’s hair in order to claim his plush mouth in a kiss. Cas seems happy to reciprocate, leaning onto his forearms and drawing it out. They’ll be tied together for a while, and where in the past this would be undoubtedly the most uncomfortable and sickening part of the whole experience, right now Dean feels nothing but contentment. He scents Cas’s joy—cleaned linens and freshly cut grass—and he wonders what he smells like to Cas right now.

When he’s soft enough, Cas lifts himself up far enough to slip out of Dean’s body, and he quickly turns them on their sides, nose to nose on dirty sheets in a dingy motel room. But Dean doesn’t notice anything except the way Cas’s eyes are shining with adoration.

“Why’re you looking at me like that?” he asks quietly, reaching out to intertwine their fingers.

“Because I think you’re beautiful and every time we’re together I get to see another beautiful thing about you. These past few weeks of getting to know you have been incredible, and if I could have the chance to truly be your Mate… I would be the luckiest man alive.” Cas’s earnest tone makes even the sappiest words sound like the truth; Dean wishes it could be true so much he aches with it. He doesn’t realize his scent has changed from sated to miserably sad until Cas is curling long fingers through his hair and shushing him.

“I’m right here, Dean,” Cas murmurs. “It’s okay. We’ll be okay.”

“How can you be so sure, Cas?”

Cas wraps his arm around Dean’s waist to bring Dean into a tight embrace. “I don’t suppose it will be easy, but I’m willing to work for it if you are. We’ll just make it up as we go.”

They hear a series of knocks on the door.

**Author's Note:**

> sorry about that
> 
> [on tumblr](http://profound-boning.tumblr.com/post/167947281029/)


End file.
